Safety arrester cables, in the state of the art, are applied where connections which are rigid per se, are to be able to be destroyed under certain conditions, and it is to be ensured that the part which has broken away may not fly off in an uncontrolled manner and on account of this create larger damage or endanger people.
In motor racing sport it is often the case that with collisions of two vehicles, or of a vehicle with the bordering of the racing track, the wheel axles and their suspension break, and the wheel flies off in an uncontrolled manner or is catapulted away. People at the edge of the racing track have often been injured or even killed by way of this. This problem is known and safety regulations have been imposed to the extent that the wheels must be connected to the body of the vehicle via a safety arrester cable. Until now many grave accidents have been avoided by way of this safety precaution, but despite this, the safety arrester cables applied until now still have an insufficient effect.
On the market today there are fibers or yams manufactured from these which have a tear strength which is a multiple greater than that of steel fibers. Whilst for example steel fibers have tear strength of 3.0 cN/dtex, carbon fibers have tear strength of 20 cN/dtex. The relatively elastic m-aramide fibers also have a tear strength of 4.7 CN/dtex, whilst the rigid p-aramide fibers have a tear strength of 19 CN/dtex and modem PBO fibers even have tear strength of about 37 cN/dtex. Safety arrester cables which are manufactured from these modem highly tear-resistant fibers, such as carbon fibers, p-aramide fibers and PBO fibers are capable of accommodating tensile forces which indeed far exceed the forces which actually occur.
Accordingly such safety arrester cables have been manufactured of corresponding highly tear-resistant plastic fibers, wherein the corresponding yams of such highly tear-resistant fibers have been endlessly wound between the two end attachment eyelets. The corresponding fibers as a result of this all run parallel to one another. With regard to those accidents which were investigated, one could ascertain that the cable stood up to the forces occurring between the two attachment eyelets, whilst it was the attachment eyelets which were broken. This is not very surprising since the highly tear-resistant materials usually have an extension up to the breakage of 1.5 to maximally 3.5 percent. This in principle could also be compensated by way of manufacturing a correspondingly long safety arrester cable. This however cannot be done since on account of this there would exist the danger that the wheel which is attached to the arrester cable could impact the driver. Added to this is the fact that it is indeed in motor racing sport that an as light as possible safety arrester cable with an as low as possible air resistance is desired. Thus it is no solution to manufacture the safety arrester cables of a less high-strength but more elastic material and to design the cable accordingly thicker.
The problem may only be solved if the cable has the best possible work-to-break-energy. This has already been attempted to be achieved according to GB 2,373,561 A by way of providing the safety arrester cable with an impulse-absorbing means. Here an inner cylinder which is to be deformed and onto which the safety arrester cable is directly tabbed, is arranged in an outer cylinder. Such a solution however not only leads to weight problems but also material problems and practically merely shifts these from the cable to the shock-absorbing element.
At present, in formula 1 motor racing sport it is essentially the safety arrester cables according to WO 03/048602 of the applicant which are used. These have also proven their worth and fulfill all the regulations of the FIA.
However these regulations are to be amended since with regard to the plastic, reservations are made with regard to the plastic that their ageing and UV loading could lead to uncontrolled deficiencies in quality. For this reason purely plastic cables will no longer be permitted.